Apparatus for drying insulated wire



1934- c. R. AVERY ET AL 1,969,666

APPARATUS FOR DRYING INSULATED WIRE Filed Oct. '7, 1951 4 Sheets-Sheet 1 l7 F125. 55 I lNVENTUFIS C. E. AVERY BY /'7. KRESS ERM A TTORNEY 1934- c. R. AVERY ET AL 1,969,666

APPARATUS FOR DRYING INSULATED WIRE Filed 001;. 7, 1931 4 Sheets-Sheet 2 lNVE/VTORS C. R. /1VEF\Y H. KHESS WH/VEY Aug. 7, 1934. c. R. AVERY ET AL APPARATUS FOR DRYING INSULATED WIRE Filed Oct. 7, 1931 4 Sheets-Sheet 3 /NVENTOR5 -C. R. AVERY H. KREEE 5) 6 t ATTURNEV Aug. 7, 1934. c. R. AVERY ET AL APPARATUS FOR DRYING INSULATED WIRE Filed Oct. '7, 1951 4 Sheets-Sheet 4 FIG. 6.

lNVENTURS C. FY. A VERY H. KRE55 5) Q ATTORNEY Patented Aug. 7, 1934 UNITED STATES APPARATUS FOR DRYING INSULATED WIRE Gordon R. Avery, Westfield, and Heinz Kress, Jersey City, N. J., assignors to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application October 7, 1931, Serial No. 567,344

4 Claims. (Cl. 34-48) This invention relates generally to the coating of strands, and more particularly to apparatus for and a method of coating textile insulated wire with an organic material such as cellulose acetate.

In the manufacture of textile insulated wire, it is sometimes difficult to apply the insulation to the wire so that it shall adhere closely to the strand of wire. There is a tendency for the textile to fray, as a result of which short freeended fibres of the textile extend outwardly from the main body of the insulation. These short fibres may under certain circumstances tend to absorb moisture in varying quantities, and when the wires are used in close proximity to each other, in communication systems such as telephone circuits, there may be a tendency in some instances to cause some interference. I

Objects of the present invention are to improve the apparatus and methods employed in the coating of textile insulated wire, and to incorporate therein new and improved features of safety and control.

Briefly, the preferred embodiment of the invention contemplates the provision of one or more strand coating units, each having immersion and drying chambers. Motor-driven, multi-grooved capstans carry the strand through the immersion and drying chambers a plurality of times, and wiper dies remove excess fluid from the strand before each drying. A single heater supplies heated air to the drying chambers of all of the units through supply and discharge ducts, and an outlet for discharging a portion of the vapor laden air as it returns from the drying chamber and an inlet for replacing the air so discharged with fresh air enables the keeping of the vapor content of the air below a. predetermined maximum. The admission of air to the drying chamber is controlled by a valve operated by door latching mechanism, and the development of excessive pressures is prevented by a plurality of explosion reliefs.

Other features and advantages of the invention will become apparent from the following detailed description of one embodiment thereof, by'means of which the method may be practiced, reference being had to the accompanying drawings, wherein Fig. 1 is a side elevational view, partly in section, of a wire coating machine;

Fig. 2 is a front elevational view, partly in section; Fig. 3 is an enlarged plan view taken on the line 33 of Fig. 2; 1

Fig. 4 is an enlarged front elevational vie taken on the line 4-4 of Fig. 3;

Fig. 5 is a schematic plan view of the hot air system, and

Fig.6 is a schematic front elevational view of the hot air system.

In the preferred embodiment of the invention, a plurality of wire coating units, preferably four, is built up and mounted in a row, as shown in Fig. 2, and two such rows are placed back to back, as shown in Fig. 1. This arrangement of eight units constitutes one machine, and each machine has certain apparatus common to and serving the eight units, as will be more particularly set forth hereinafter.

Referring particularly to Figs. 1 and 2, 10 designates wire coating units having air admission and discharge chambers 11, drying chambers 12, and immersion chambers 13. The several shambers may be constructed of metal in any desired manner, and each unit may have a complete set of confining walls, or adjacent units may have common side walls, as shown at 15 in Fig. 2.

The air admission and discharge chambers 11 are provided with inlet openings 16 adjustable in area by means of the slidable dampers 18, and outlet openings 17. The chambers 11 are in communication with the drying chambers 12, and a butterfly valve 20 is provided in each of the chambers. When the butterfly valve is in vertical position, air may pass down into the drying chamber from the inlet 16, and from the drying chamber to the outlet 17, and when the butterfly valve is in horizontal position, air is prevented from entering the drying chamber 12, and is bypassed directly to the air outlet 17 through the baffle 21, which is so constructed and arranged as to offer substantially the same air resistance as does the drying chamber.

Centrally located in the drying chamber, and secured to the back thereof by any satisfactory means such as bolts is a box-like member 24 that serves as a baflle. This baflle begins a short distance below the top of the drying chamber and terminates a short distance above the bottom of the drying chamber and it extends from front to back of the chamber. The top, bottom and .front walls of the baffle member are solid, th

side walls contain rectangular apertures 25, the member is hollow, and open on the side that abuts against the rear wall of the drying chamber. There is a rectangular aperture 26 in the rear wall of the drying chamber 12 directly behind the baflle member 24. By means of the apertures in the side walls of the baffle, and the aperture in the rear wall of the drying chamber, the latter may be in communication with the outside air. no

However, the aperture-in the rear wall of the drying chamber is normally covered by a thin metallic sheet such as tin or aluminum, which is secured between the bafile and the rear wall of the drying chamber. Likewise, the apertures in the side wall are covered with similar metallic sheets held in place by bolted flanges. These coverings for the apertures serve as explosion reliefs to normally prevent the air in the chamber from flowing out other than through the air outlet 17, but to prevent the formation of excessive pressures.

Directly above the bafile 24 is mounted a capstan 28 provided with a plurality of circumferential grooves 29. The capstan 28 is driven by an electrical motor 32, of any suitable type, at the base of the machine, through the drive shaft 30 and gear box 31. The shaft 30 is mounted directly behind the aperture 26 in therear wall of the chamber 12, and may be reached, for inspection, lubrication and repairs, by removing the baflle 24. As shown in Fig. 1, the air admission and discharge chamber does not extend out to the front of the machine. In order to prevent the flow of air across the drying chamber above the capstan 28 and in front of the butterfly valve, a small gate 34 is hinged at 35. This gate may be maintained in horizontal position by the latch 36, if the butterfly valve is also in horizontal position. When the butterfly valve is moved to vertical position, it releases the latch 36, which permits the gate 34 to drop to vertical position. Rotatably mounted on spindles in the drying chamber 12 are inter-pass sheaves 40, 41, 42, 43, 44, provided with circumferential grooves corresponding to the grooves on the capstan 28. Singly grooved sheaves or pulleys 46 are provided at the top of the machine on brackets 47 for carrying a strand of wire as it enters and leaves the drying chamber. A sheave or pulley 48 is also providedinside the drying chamber 12 for guiding the strand of wire from the sheave 46 to the capstan 28.

The drying chamber 12 is provided with hinged, substantially air-tight doors 50 having interlocking edges. each other and to the walls of the drying chamber, and are provided with packing material such as felt, to prevent the escape of air from the chamber 12. A latch controlling handle 51 is provided for manually latching each pair of doors 50. A pinion 52 carried by the handle shaft 53 meshes with a pinion 54, which in turn meshes with the rack bar 55 carried on the interior of the door. The rack-bar has 9. lug 56 at the'upper end thereof that enters a.recess 57 in the slidable rack bar 58 when the doors are closed. The bar 58 has teeth 59 engageable with the pinion 60 which is mounted on the rock shaft 61 of the butterfly valve. The shaft 61 has a limited angle of rotation independently of the pinion 60, and is rotatably engaged by the pinion outside the angle of independent rotation. An arm 65 is keyed to the shaft 61 in such position that it is horizontal when the butterfly valve 20 is in vertical position. A tension spring 67 has one end secured to the outerend of thearm 65 and the other end secured to the top of the drying chamber. A recess is provided at 66, into which the lower end of the bar 55 may move whereby the door may be latched and its opening without turning the handle 51 prevented.

In Fig. 2, the doors of the drying chamber at the extreme right are shown in latched position.

The doors of the right center chamber are shown in unlatched position. The operation of the The edges of the doors are fitted to.

latching and butterfly valve controlling mechanism is as follows: when a machine is in operation, the butterfly valve is in vertical position with the upper portion covering the apertures in the baille 21 and the lower portion extending toward the capstan 28, the arm 65 is in horizontal position, the lug 56 is in the recess 57, the rack bar 55 is in its lowest position with its lower end engaging the recess 66, and the handle 51 is in the extreme left hand position. I When the handle 51 is moved to the right, the pinions 52 and 54 cause the bar 55 to move upwardly and disengage the recess 66. At the same time the bar 58 moves upwardly and rotates the pinion 60 which engages the rock shaft 61 and causes the arm 65 to. move angularly in a. counter-clockwise direction. The spring 67 tends to urge the arm 65 in a clockwise direction, until the spring crosses the axis of the shaft 61, when the arm 65 is urged in a counter-clockwise direction. The angle of independent rotation of the rock shaft lies in the direction of rotation of the pinion, so that the spring snaps the arm 65 into vertical position.

The butterfly valve is thereby brought into horizontal position, closing the air passages to the drying chamber and opening the apertures in the baflle 21 to by-pass the air to the outlet. The

doors may then be pulled open. When the handle is moved to the left to latch the doors, the

process aboveoutlined is reversed, and when the spring passes the axis of the rock shaft 61 as the arm 65 moves clockwise, the spring snaps the arm into horizontal position, thereby opening the butterfly valve and closing the apertures in the baffle 21.

At the bottom of the drying chamber, a hinged partition 70 is provided to confine the flow of air substantially entirely to the drying chamber and to prevent the coating fluid from splashing up into the drying chamber. The partition has slots 71 through which the traveling strand of wire may pass,. and is hinged at the back to permit it to be swung upwardly and back against the back wall of the chamber to afford access to the coating chamber. on the rear wall of the drying was to be engageable with the partition is a lever 72 pivoted at 73 to allow its lower end to swing away from the wall. A rod 74 is mounted so as to have one end in contact with the upper portion of the lever 72 and the other end extending slightly outside the inner wall of the door 50 when the door is open, and the rod is slidably urged toward the door by the spring 75. When the door is closed, the rod 74 is moved longitudinally, thereby rocking the lever 72 and causing its lower end to move forward. If the,partition 70 is in upright position when the door 50 is closed, the rocking of the lever 72 will cause the partition to be displaced, and it will drop down chamber into the position between chambers 12 and 13.

The chambers 13 contain the fluid which is to be applied to the wire, and the apparatus for coating the wire and wiping away the excess fluid. This apparatus is shown in Fig. 2, and more clearly in enlarged views in Figs. 3 and 4, in connection with which it will presently be described.

The chambers 13 are partially separated from each other by the walls which terminate some distance above the bottoms of the chambers 13. It is thus apparent that the several chambers are in communication with each other, and that the coating fluid may be supplied from a source Mounted through. a single inlet, and that it will flow into the several chambers. An inlet pipe 81 is provided at one end of a row of machines for supplying the fluid from any convenient supply reservoir (not shown) to the chambers 13. At the other end of the row of machines is a chamber 82 in communication with the chambers 13, containing .an outlet 83 connected through a trap, 84 which may be of any convenient design, to a discharge pipe 85. Continuous flow of fluid is maintained from the inlet pipe 81, through the chambers 13, and out through the discharge pipe 85. The trap 84 is used to prevent the escape of gases into the discharge pipe 85 and in case of fire, to prevent the fire-from working back through the discharge pipe 85 to the supply reservoir. A float 87 within the chamber 83 serves to operate any suitable warning device, if the fluid in the chambers 13 falls below the desired level. A baille plate 88 mounted in each of the chambers 13 a short distance from the bottoms thereof prevents a substantial portion of the fluid admitted through the inlet pipe 81 from flowing into the several chambers along the bottoms thereof, and causes it to flow over the top of the baille plate 88 to the next chamber. In the rear of the chamber 13, and above the normal level of the fluid is an inlet 89 connected to a valve controlled source of carbon dioxide, (not shown). The purpose of this inlet is to permit the admission of' carbon dioxide to the units in the event that a flre breaks out in any one of them.

Mounted on the rear wall of each of the chambers 13 and extending a short distance up into the drying chambers 12 is a pair of members 95 comprising metalic bars having channels or grooves on the inside edges thereof. On the rear wall of each of the drying chambers 12, and extending between the lower end of the baffle 24 and the rear edge of the partition '70 is a pair of similar grooved or channeled bars 96, having a plurality of cutaway portions or notches 97. The members 96 are mounted in alignment with the members 95, and are of sufllcient depth that the partition '70, when in vertical position, stands behind and clears the grooves in the members 96. Also, the slots '71 in the partitions '70 are of sufflcient width to clear the members 96.

Referring now particularly to Figs. 3 and 4, 100 is a metal plate having depending portions 101 at the rear corners thereof slidable in the grooves in the members 95. The plate 100 has a latch 102 operated by a handle 103, the latch engaging notches in the members 95 to retain the plate 100 in position. The plate 100 is also provided with a handle 104 by means of which it may be moved upwardly when the latch 102 is released. As the plate is moved upwardly, the depending portions 101 slide out of the grooves in the members 95 and into the grooves in the members 96, and if the plate is raised to a suflicient height, the latch 102 will engage the notches 9'7, thus holding the plate in raised position and giving access to the interior of the chamber 13, and also to mechanism carried by the plate.

The plate 100 carries on its under side a depending arm 105 in which is rotatably mounted the immersion roller 106. This roller has rigidly mounted around its periphery a plurality of transverse rods 107 each of which has a plurality of annular grooves, preferably six in number, ar-' ranged so as to be in circumferential alignment around the roller. By means of this arrangement, fluid may reach the inner side of a strand carried in the grooves around the roller.

Above and to one side of the'immersion roller 106 is mounted a pair of wiper dies 110 and 111. The die 110 is accurately grooved for a strand of a given size, and is keyed to a shaft 113 that is journaled on a supporting member carried by the plate 100, and has keyed to the front end of its shaft a pinion 112. Adjacent to the wiping die 110 and removably mounted within the chamber 13 independently of the plate 100 is a frame 115 normally maintained in position by the spring retained latch 116. The frame 115 carries a bracket 117 to which is pivoted at 118, intermediate its ends, an arm 119 which has rotatably mounted thereon a shaft 120. The shaft 120 has keyed thereto the wiper die 111, and also at its front end the pinion 121 which meshes with thepinion 112. The wiper die 111 is accurately grooved in complementary arrangement with respect to the die 110, so that the high and low portions of each are in alignment with the low and high portions respectively of the other, and the grooves in both dies are so formed that the openings therebetween, through which the wire passes, are substantially circular.

A tension spring 122 has one end secured to the frame 115 and the other end secured to the arm 119, and tends to urge the wiper die 111 toward the die 110. By means of this arrangement, the die 111 may move away from the die 110 to permit enlargements or irregularities such as knots in the strand to pass through, and the spring 122 will cause the die 111 to follow and contact with the strand at all times. screw 123 is provided by means of which the minimum distance between the two dies may be varied. Coextensive with the wiper dies is a perforated pipe 124 mounted on the rear wall of the chamber 13, and connected to a source of solvent liquid (not shown) whereby the solvent may be sprayed on the dies at desired intervals, for cleaning the dies.

Refen'ing again to Figs. land 2, a motor 130 is mounted at one end of each row of machines, and is connected through a gear box 131 to a shaft 132 which extends horizontally across the row of machines. A switch 133 controls the motor 130. Mounted on the shaft 131 in front of each of the wiper dies 111 is a gear 134 connected to the shaft 132 by a spring pressed clutch 135. Directly above each of the gears 134 is a rotatable shaft having keyed thereto a pinion 136 meshing with the gear 134, and another pinion 137 meshing with the pinion 121. In this way each set of wiper dies is driven from a common drive shaft through a clutch that prevents overloading. The provision of common drive shafts for all dies permits them to be operated continuously and prevents sticking due to accumulation of cellulose acetate and lint.

As shown in Fig. 2, mountings 140 and 141 are provided in front of each machine for supply and take-up reels respectively, and each of the latter is individually driven through suitable gear ing including a slipping clutch (not shown) from the drive shaft 30 that operates the capstan 28. A switch 142 is provided for controlling the operation of each of the motors 32 that operate the drive shafts 30. I

Referring now particularly to Figs. 5 and 6, 150 is a schematic representation of a heater, which may be of any suitable type, such, for example, as a steam, electric, or oil fired heater, for heating air. An inlet is provided at 151, through which fresh air may enter the heater, and a duct 152 is provided'through which heated An adjustment air may be drawn from the heater 150 by the blower 153 operated by any convenient means 154 such as a belt driven or chain driven pulley. From the blower 153, the duct 155 leads to the top of a unit of coating machines, and is there connected to each of the air inlets 16. A discharge duct 156 for each row of units, connected to each of the air outlets 17 of the units in the row conducts the air from the drying chamber back to the heater 150, entering at 157. The discharge duct 156 has apertures 159 directly above each of the outlets l7, and a sheet of metallic foil 161 is secured over each of the apertures in any convenient manner to serve as an explosion relief. A portion of the air is reheated and recirculated through the system. In order to permit the continual replacement by fresh air of a portion of the air returning through the duct 156, and to keep down the vapor content of the air in the system, an outlet duct 158 having its entrance adjacent to the end 157 of the duct 156 and having therein a damper 162 is provided, whereby a controlled portion of the returning air from the drier may be discharged. The duct 158 leads to a reclaiming plant (not shown) where the vapor absorbed by the air in the drier may be removed and reclaimed.

When it is desired to apply a coating to a textile insulated wire by means of the apparatus hereinbefore described, a reel containing the wire is mounted on the supports 140, and a take-up reel is mounted on the supports 141. The end of the wire is passed over one of the sheaves- 46, down over the sheave 48, down against one of the grooves in the capstan 28, which serves as a guide, around the lower half of the immersion roller 106 which has been raised out of the chamber 13, up through one of the grooves in the wiper die 110, to the capstan 28, over the capstan 28, under the sheave 43, over the sheave 44, down and under the sheave 40, across to and under the sheave 41, up and over the sheave 42, across to and over the capstan 28, which brings the end of the wire again to the beginning of its path to the immersion roller 106. The stringing of the wire is continued in repetition of the same path until preferably six paths have been completed. The strand is then arranged in an additional path around the interpass sheaves to insure perfect drying, is passed twice around the capstan 28, across to and under the sheave 42, up through the top of the machine, and around i the other of the sheaves 46, and down to the takeup reel. The passage of the wire under the sheave 43 and over the sheave 44 insures polishing action on the entire surface of the wire. After the wire has been completely strung, the plate and its associated apparatus may be lowered into position in the chamber 13, and the wire in each of the six paths will then be firmly pressed between the wiper dies 110 and 111.

While the apparatus may be used for applying many kinds of coatings to wire, it is particularly intended for use in coating textile covered wire with cellulose acetate. The coating substance may be dissolved in any volatile solvent in which it is readily soluble, acetone being especially useful for dissolving cellulose acetate. The solution is introduced into the machine through the inlet pipe 81, and is brought to the proper level, which is such that the lower portion of the capstan 106 and the wire are well immersed. The air blowerv and the wiper die operating mechanism may be started, after which the doors may be closed and latched. As previously stated, these latter operations will cause the partition 70 to drop into place, and the butterfly valve to open and admit heated air to thedrying chamber. The path of the air in the chamber is down the inlet side, across below the baifle, and up the outlet side. As a final step, the motor operating the capstan 28 and the take-up reel is started, and the machine is then in full operation.

It will be apparent that the wire will be subjected to six separate immersions and wipings, and to seven dryings. It will also be apparent that the direction of movement of the wire is at all times opposite to the direction of the flow of air. This arrangement gives a maximum drying effect, because it is equivalent to an air current having the combined velocities of the hot air and the wire, relative to a stationary point. The provision of the inter-pass sheaves 40, 41, 42, 43, 44 insures complete drying, because it provides a substantial time interval between immersions during which the wire is subjected to contact with the blast of hot air.

One purpose of drying the coating is to vaporize substantially all of the acetone from the textile covering of the wire, leaving thereon a coating of cellulose acetate only. The acetone serves merely as a vehicle for applying the organic ester to the wire while the hot air absorbs and carries away the acetone vapor. Acetone is an inflammable liquid, and some concentrations of acetone vapor in air, particularly between approximately two and one-half per cent and thirteen per cent by volume are explosive, from which it follows that for maximum safety the acetone content of the hot air must be kept outside of this range. It has been found preferable to keep the acetone content below one and one-half per cent by volume. The arrangement of the air system previously described, which provides for the continuous admission offresh air, and removal of acetone laden air, enables the keeping of the acetone content within the desired limits. As a means of checking the mixture as it leaves the drying chamber, a small tube 160 provides means for conducting samples of the air to analyzing apparatus (not shown).

For the protection of the apparatus and the operator, safety features include the butterfly valve control, the foil covered apertures in the baflle and in the discharge ducts, the use of completely enclosed motors and oil immersed switches, and the positioning of electrical fuses at a safe distance. If, for any reason, excessive pressures should be built up in the drying chamher, there is no danger that they may reach explosive magnitudes, .because the pressures will rupture the thin metallic foils, and will be relieved through the rear of the machine, where there is little danger of injury. The butterfly valve arrangement prevents opening the doors while the hot air is being admitted to the drying chamber, and eliminates the possibility ofinjury to the operator by exposure to a blast of hot air.

While portions of the foregoing description of apparatus and operation refer to one unit, it is to be understood that all of the units constitutnumerous variations may be made in the apparatus and its operation without departing from the scope of the invention as set forth in the appended claims.

What is claimed is:

1. In an apparatus for coating wire, a drying chamber having air inlet and discharge ports, a source of heated air, supply and discharge ducts connecting the source of heated air to the ports, a by-pass baflle positioned between the inlet and discharge ports, and having apertures therein, a valve for causing the heated air to flow into and out of the drying chamber when in one position, and through the by-pass baflle when in another position, doors for the chamber, and a latching member carried by a door and operatively engageable with valve operating means to admit or by-pass heated air.

2. In an apparatus for coating a stand, a drying chamber having an aperture in one wall thereof, a hollow baflle having an open side mounted over the aperture in the wall of the chamber and having apertures in the side walls thereof,

and easily rupturable coverings for the apertures in the drying chamber and baflle.

3. In an apparatus for coating a strand, a drying chamber having an aperture in one wall thereof, a source of .air connected to the drying chamber, a hollow baflle having an open side mounted over the aperture in the wall of the chamber and having apertures in the side walls thereof, and pressure rupturable metallic coverings secured over the apertures in the wall of the chamber and in the bafile.

4. In an apparatus for coating wire, a drying chamber having an aperture in one wall thereof, a source of heated air, a hollow bafile having an open side and apertures in the side walls there- 

